1. Field of the Invention
The present invention relates in general to electrical power distribution design, implementation and repair devices and, in particular, to a system and circuit for identifying which one of a group of circuit breakers is associated with a particular, selected branch circuit within a facility.
2. Background Art
When electrical work needs to be performed on an electrical system in a building or facility, it is usually necessary to trace and identify which circuit interrupter device (i.e., circuit breaker or fuse) is supplying power to a specific AC power branch circuit.
Manual identification of the fuse or circuit breaker can be accomplished by removing each fuse or opening each circuit breaker, thereby disrupting the power flow through the circuit. Each test point must subsequently be examined to determine whether the power to the test point has been disconnected. This method is not only time consuming, but also may not be feasible in situations where it would be hazardous to interrupt the power flow to certain branch circuit outlets, i.e., in a hospital or in environments where there are computers in use without backup power.
Alternatively there are currently available a number of circuit testers for identifying the circuit interrupting device that is supplying power to a specific outlet receptacle. These testers employ a variety of techniques to differentiate one circuit breaker from the rest. All of these pre-existing devices have at least one thing in common, they all consist of two separate units, a identification signal generator (referred to as a transmitter) and a signal receiver, which inject and then receive this signal over the AC wiring.
Consequently, it is an object of the present invention to provide a circuit location device that is simpler to couple to one of a plurality of branch circuits of a facility.
One pre-existing tester pair creates a magnetic field on the AC wiring and then detects that magnetic field proximate the circuit interrupter devices. Unfortunately, the magnetic fields created are easily coupled between AC wire lines, thus creating potentially false identification signals. Further, using magnetic fields as signal medium, in turn, necessitates the use of a radio frequency receiver for detection at the circuit interruptor devices box.
Accordingly, it is another object of the present invention to provide a device that provides more reliable identification of circuit selection. It is an associated object of the present invention to obviate the need for radio frequency receiver by eliminating the use of magnetic field identification. As a result, detection can be accomplished at significantly larger distances and with less error in noisier environments than with the magnetic field approach.
Depending upon the type of tester device used, the end user may also be required to calibrate for the sensitivity of the device either by manually adjusting same or by allowing for differences in sensitivity by independent observation of sensitivity data provided via a signal strength meter, bar graph display or other approach in order to properly identify the correct circuit interrupting device. Receivers with manual adjustment as well as those with analogue or digital readouts (signal strength meters) can be quite difficult to use especially if the end user has no prior experience with such instruments. Furthermore, since the strength of the identification signal is a function of permanently altering line impedance and capacitance, the amplitude of the identification signal varies. However, pre-existing receiving devices always detect the breaker in question by determining which breaker is reflecting the largest signal amplitude.
Accordingly, it is yet another object of the present invention to provide easier operation and time savings to an end user by eliminating the need for manual calibration and thereby also eliminating the potential for user error associated with same.
These and other objects will be apparent to those of ordinary skill in the art having the present drawings, specification and claims before them.